Preformed composite step tread



25, 1941. B CARLSQN 2,236,465

PREFORMED COMPOSITE STEP TREAD Filed May 31, 1938 IN VEN TOR. ARNOLD 8. CA

Patented Mar. 25, 1941 UNITED STATES PATENT OFFICE 2,236,465 i i PREFORMED COMPOSITE s'rEP TREAD "Arnold B. Carlson, Aurora, Ill.

' Application May a1, 1938, Serial No. 210,805

1 Claim.

It contemplates more especiallythe provision of a preformed stair tread that consists of composite sheets of materialand pads which are assembled as a unit to define a carpeted stair tread.

Stair treads of .numerous' types have heretofore been proposed, these not having proved entirely satisfactory owing to the cost of manufacture and the care that must be exercised in assembling composite materials for retention in position on stair steps. It is proposed to combine a blank metallic sheet with a preformed pad and a strip of carpet so as to constitute a permanent composite unit adapted for ready application to the step of a stair without entailing any appreciable time or effort. This affords an improved protective tread for wood stairs that is padded and carpeted to conform with the other floors of the house and to have unusual wearing qualities employed with comfortable stepping characteristics. One object'of the present invention is to simplify the constru'ction and provide an improved composite stair tread.

Another object of the invention is to provide a metallic member with a preformed pad and carpet strip for permanent assembly therewith for attachment to stair treads.

Still another object is to provide a preformed metallic blank shaped and flanged in a sequence of steps to provide a self-contained and preformed composite stair tread embodying the usual carpet and pad to minimize wear.

A further object is to provide a method of forming composite stair treads which consists in blanking a metal sheet so as to permanently retain a carpet having an interposed preformed pad.

A still further object is to provide a more simple and less expensive method of forming a composite stair tread to embody a metallic sheet for holding the preformed strip of carpet and pad in position to constitute a ready-made stair tread adapted for instantaneous application.

Still a further object is to provide a composite 50 stair tread having a metallic sheet provided with a series of edge serrations to retain a strip of carpet and a pad in predetermined relation.

Other objects and advantages will appear from the following description of an illustrative em- 55 bodiment of the present invention.

In thedrawingz u I Figure i is a fragmentary plan view of a metallic sheet that is blanked to provide the first step in the production of a padded stair tread,-

Figure-,2 is a fragmentary perspective view of 5 'a corner. of, the metallic sheet shown in Figure 1 illustrating. the succeeding step of upturning the serrated edge preparatory to receiving a pad.

Figure 3 is. a fragmentary perspective sectional view'showing the next step of bumping the flangediser'rated edge so as to enable the reception pf a strip of carpet thereon subsequent to afligingajpreformed pad to the surface thereof. "Figure 4 is a fragmentary perspective sectional view similarjto Figure 3 and showing the application of a strip of carpet to the metallic mem-. her for disposition beneath the peripheral flange. Figure 5 is a fragmentary perspective sectional view show-ing the next step of turning down the peripheral'or .flanged edges so that the serrations will project through the carpet and engage the bottom surface of the metallic. sheet so as to holdjthe' componentparts. in assembled relation. Figure. dis a side view in elevation of arfinished composite. stair tread embodying features of the 25 present invention. v

Figure .7 is a plan view of the finished stair tread shown in Figure 6 with the curved forward edge or ends thereof shown to the right in Figure 7 rather than the left as m Figure 6.

Figure 8 is a fragmentary perspective view of two steps of a stairway showing the preformed stair tread attached thereto in the contemplated manner.

The structure selected for illustration com- 35 prises a preformed sheet of metallicmaterial Ill that is initially of substantially rectangular configuration preparatory to stamping so as to form individual rectangular sheets having serrated edges ll terminating in cut-off corners l2. A serrated peripheral edge ll defines teeth l3 that serve to retain a strip of carpet in stretched positzion in a manner which will appear more fully hereinafter.

After the metallic sheet material has been blanked to form sheets I!) with serrated edges ll defining the teeth I3 interrupted by the cutoff corners l2, the sheet I0 is placed in a suitable die and blanked to define an upstanding peripheral flange u (Figure 2) so that the teeth 13 will extend normally to the surface of the sheet 10. The flange I4 is somewhat wider than the depth of the teeth l3. Thereupon, the sheet I0 is placed in a bumping die" so as to provide an additional peripheral flanged portion I5 extending at an angle of substantially 30 so as to turn the teeth in a downward direction for spaced relation to the surface of the sheet In (Figure 3).

This affords the application of a preformed carpet pad l6 which may be glued or otherwise attached to the top surface of the sheet ID as commercial practice may dictate. For that matter, the pad 16 may be attached to the sheet ID by means of staples [1 (Figure '7) or merely adhesively applied thereto so as to cover the .greater part of the top surface of the sheet In, terminating short of the peripheral flanged portions H-l4--l5. PreparatOry to securing the preformed pad l6 in any suitable manner to the top surface of the plate It], the latter is shaped so as to provide an arcuate nose l8 (Figure 6) that envelops the forward edge IQ of standard steps 20 defining a stairway 2!.

The pad I 6 does not extend over the nose I 8, but terminates short thereof so as to cover only that part of the sheet I which is above the top surface of the steps 20. For that matter, the pad [6 also terminates short of the peripheral edges of the sheet Illso as to enable the insertion of a strip of carpet 22 in the serrated flanges H--l4-l5 that extends around the entire periphery of the sheet H). To this end, the strip of carpet 22 is shaped to conform substantially with the finished surface area of the sheet l0 so as to be inserted underneath the peripheral open flange l4l5 disposed therearound (Figure 4) preparatory to being subjected to a bumping operation which turns the flange I l-l downwardly so that the teeth l3 project through the strip of carpet 22 and engages the confronting surfaces of the sheet ill to permanently hold the carpet 22 in stretched position above the pad I 6 in permanent assembled relation with the sheet Hi.

It should be noted that in the last bumping operation that turns the flange l4--l5 downwardly, the teeth I3 extend somewhat inwardly toward the finished rounded peripheral edge 23 so as to impart a stretching effect to the strip of carpet 22, this being due to the fact that the serrated edges is reversely bent to a slight degree during the last step in defining a peripheral finished flange l4l5--23. During this last operation the cut-off corners l2 serve to form meeting oblique edges 2425 so as to define a peripheral flange of rectangular configuration to securely hold the carpet strip 22 in taut position against possible removal.

It will be observed, therefore, that a simple and inexpensive method has been provided to form stair treads of composite materials that will conform to a carpeted floor and afford comfortable treading up and down the steps with minimum wear. This composite self-contained and preformed tread unit is attached to the steps 20 by having the nose l8 engage the forward rounded edge l9 thereof. They are then held in position against removal by having small nails or other suitable fasteners 26 pierce the carpet 22, the pad l6 and metallic sheet Ifl near the rearward finished flange I l-l5 of each unit I0. This results in an improved preformed composite stair tread that is simple and inexpensive in construction and possessed of improved functional features.

Various changes may be made in the embodiment of the invention herein specifically described without departing from or sacrificing any of the advantages of the invention or any features thereof, and nothing herein shall be construed as limitations upon the invention, its concept or structural embodiment as to the whole or any part thereof except as defined in the appended claim.

I claim:

A composite stair tread comprising a preformed metallic plate shaped to cover the tread of a step, a preformed pad of uniform thickness applied to the top surface of said metallic plate, said pad being smaller in surface area than said metallic plate, a preformed carpet shaped substantially to conform with the size of said metallic plate, and bent serrated edge flanges integrally formed on all edges of said metallic plate, the said serrated flanges projecting downwardly through the carpet to permanently retain the carpet under tension in all directions along its entire perimeter over the pad and top surface of said plate.

ARNOLD B. CARLSON. 

